The present invention relates to a turbine bucket for a gas turbine stage and particularly relates to a first-stage turbine bucket airfoil profile.
In recent years, advanced gas turbines have trended toward increasing firing temperatures and efforts to improve cooling of the various turbine components. In a particular gas turbine design developed by General Electric Company, a high output turbine that uses a combination of steam and air cooling to meet a 60% combined cycle efficiency is undergoing development. It will be appreciated that the design and construction of the turbine buckets and particularly the buckets of the first turbine stage of that turbine require optimized aerodynamic efficiency, as well as aerodynamic and mechanical bucket loading. Additionally, the interaction between the stages of the turbine is a factor in determining the overall turbine efficiency.
General Electric Company has developed an optimal first-stage turbine bucket airfoil profile to achieve a 60% combined cycle efficiency in producing 50Hz electrical power in what has become known as the MS9001 turbine system. See, for example, U.S. Pat. No. 6,461,110. Efforts have been made to achieve a 60% cycle combined cycle efficiency in generating 60 Hz electrical power. Meeting system requirements of efficiency and loading in such a first stage turbine bucket in a high output (400MW) turbine producing 60 Hz electrical power, such as the MS7001H turbine developed by General Electric Company, has become a challenge. An airfoil profile that meets the efficiency and stage loading goals of the turbine while avoiding undesirable and even potentially unsafe vibration leading to blade fatigue failure has yet to be achieved.
In one aspect, there is provided a turbine bucket having a bucket airfoil in an envelope within xc2x10.100 inches in a direction normal to any bucket surface location wherein the bucket airfoil has an uncoated nominal profile substantially in accordance with Cartesian coordinates values of X, Y and Z set forth in Table I carried only to three decimal places wherein Z is a perpendicular distance from a plane normal to a radius emanating from the turbine centerline and containing the X and Y values with the Z value commencing at zero in the X, Y plane at the radially innermost aerodynamic section and X and Y are coordinates defining the profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form the complete bucket airfoil shape.
In another aspect, there is provided a turbine bucket having a bucket airfoil shape in an envelope within xc2x10.100 inches in a direction normal to any airfoil surface location wherein the airfoil has an uncoated nominal profile substantially in accordance with Cartesian coordinates values of X, Y and Z set forth in Table I carried only to three decimal places wherein Z is a perpendicular distance from a plane normal to a radius emanating from the turbine centerline and containing the X and Y values with the Z value commencing at zero in the X, Y plane at the radially innermost aerodynamic section of the airfoil and X and Y are coordinates defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form the complete airfoil shape.
In another aspect, there is provided a turbine bucket having an uncoated nominal airfoil profile substantially in accordance with Cartesian coordinates values of X, Y and Z set forth in Table I carried only to three decimal places wherein Z is a perpendicular distance from a plane normal to a radius emanating from the turbine centerline and containing the X and Y values with the Z value commencing at zero in the X, Y plane at the radially innermost aerodynamic section of the airfoil and X and Y are coordinates defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form the complete airfoil bucket shape, the X, Y and Z values being scaled as a function of the same constant or number to provide a scaled-up or scaled-down bucket airfoil.
In another aspect, there is provided a turbine comprising a turbine wheel having a plurality of buckets, each of said buckets having an airfoil shape in an envelope within xc2x10.100 inches in a direction normal to any bucket airfoil surface location wherein the airfoil has an uncoated nominal profile substantially in accordance with Cartesian coordinates values of X, Y and Z set forth in Table I carried only to three decimal places wherein Z is a perpendicular distance from a plane normal to a radius emanating from the turbine centerline and containing the X and Y values with the Z value commencing at zero in the X, Y plane at the radially innermost aerodynamic section of the airfoil and X and Y are coordinates defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form the complete airfoil shape.
In a another aspect, there is provided a turbine comprising a turbine wheel having a plurality of buckets, each of said buckets having an uncoated nominal airfoil profile substantially in accordance with Cartesian coordinates values of X, Y and Z set forth in Table I carried only to three decimal places wherein Z is a perpendicular distance from a plane normal to a radius emanating from the turbine centerline and containing the X and Y values with the Z value commencing at zero in the X, Y plane at the radially innermost aerodynamic section of the airfoil and X and Y are coordinates defining the airfoil profile at each distance Z, the profiles at the Z distances being joined smoothly with one another to form the complete airfoil shape, the X, Y and Z values being scaled as a function of the same constant or number to provide a scaled-up or scaled-down bucket.